contains method
Implementation
bool contains(TileIdentity other) {
final zoomDifference = other.z - z;
if (zoomDifference == 0) {
return this == other;
} else if (zoomDifference < 0) {
return false;
}
final divisor = pow(2, zoomDifference).toInt();
final translatedX = other.x ~/ divisor;
final translatedY = other.y ~/ divisor;
return translatedX == x && translatedY == y;
}